2 . With vigorous promotion and extensive participation over the past two years, waste sorting is a new trend that has reshaped the image of campuses across Beijing.

“In the past, sanitation workers sorted the garbage next to the trash cans near the dormitory, _________ a disgusting odor. On windy days, the trash was blown everywhere and we always _________ around it with our hands covering our noses,” says Sun Jiajing, a sophomore at Beijing Forestry University. “Now, we are more active in classifying waste.”

Since a revised guideline on household waste disposal in Beijing was _________ on May 1, 2020, many students have seen their campuses take on a new look that is more pleasant, tidy and appealing.

At Beijing Forestry University, about one in four students are trash-sorting volunteers.

In the Beijing No 20 High School, bins to recycle waste are placed on each floor and students on duty will set their wits to turning trash into _________.

“I received training on trash classification before taking on the role as head of the trash-sorting station. My job is to remind everyone to classify waste and recycle to the best _________,” says Ding Shuyi, a student at the school.

As China pushes _________ the “double reduction” education policy, which aims to ease the burden of _________ homework and off-campus tutoring for primary and middle school students, understanding of waste sorting has been fused into academic teaching via various innovative approaches.

“Our Chinese teachers encourage students to write poetries _________ on waste classification, math teachers lead them to do math on topics such as water conservation, while our music teachers choreographed a ‘waste sorting’ dance with the students,” says Zuo Chunyun, principal of a primary school in the suburban Tongzhou district of the capital.

Zuo adds that students in senior classes will join trash-sorting projects and map out _________ in the form of handwritten newspapers and mind maps. Decorations made from recycled materials are exhibited in the school’s corridors.

The same scene can be seen in Qianjin Primary School, Haidian district. “Garbage can be turned into __________,” says Wang Liping, the principal. “We have raised 100,000 yuan ($15,760) of charity funds by encouraging students and their parents to recycle waste, and the money was used to purchase movie screens for schools in Hotan, Xinjiang.”

According to Liu Jianguo, a professor at Tsinghua University, the implementation of garbage sorting depends on the __________ participation and unremitting efforts of society, which is conducive to the__________ of social civilization.

“Wide participation of students and school staff will help promote garbage sorting to become a new fashion in society,” adds Liu.

Official data shows that over 90 percent of the residents in Beijing have participated in waste classification, and about 85 percent can __________ categorize the garbage. But still, relevant departments are __________ to further raise the ratio.

“Our next move will be more precise supervision of groups that did __________ poorer jobs in sorting out garbage,” says a staffer with the Beijing Municipal Commission of Urban Management.

4 . The water off the coast of northwest Greenland is a glass-like calm, but the puddles (水坑) on the region’s icebergs are a sign that a transformation is underway higher on the ice sheet.

Several days of unusually warm weather in northern Greenland have caused rapid melting, made visible by the rivers of meltwater rushing into the ocean. Temperatures have been running around 60 degrees Fahrenheit — 10 degrees warmer than normal for this time of year, scientists said.

The amount of ice that melted in Greenland between July 15 and 17 this year alone — 6 billion tons of water per day — would be enough to fill 7.2 million Olympic-sized swimming pools, according to data from the US National Snow and Ice Data Center.

Each summer, scientists worry that they will see a repeat of the record melting that occurred in 2019, when 532 billion tons of ice flowed out into the sea. An unexpectedly hot spring and a July heat wave that year caused almost the entire ice sheet’s surface to melt. Global sea level rose permanently by 1.5 millimeters as a result.

Greenland holds enough ice — if it all melted — to lift sea level by 7.5 meters around the world. The latest research points to a more and more threatening situation on the Northern Hemisphere’s iciest island.

“Unprecedented (史无前例的)” rates of melting have been observed at the bottom of the Greenland ice sheet, a study published in February found, caused by huge quantities of meltwater flowing down from the surface. This water is particularly concerning because it can destabilize the sheet above it and could lead to a massive, rapid loss of ice.

And in 2020, scientists found that Greenland’s ice sheet had melted beyond the point of no return. The rate of melting in recent years exceeds anything Greenland has experienced in the last 12,000 years, another study found — and enough to cause measurable change in the gravitational field over Greenland.

At the East Greenland Ice-core Project — or EastGRIP — research camp in northwest Greenland, the work of scientists to understand the impact of climate change is being affected by climate change itself.

Aslak Grinsted, a climate scientist at the University of Copenhagen’s Niels Bohr Institute, said that they have been trying to get flights into the camp but the warmth is destabilizing the landing site.

Before human-caused climate change kicked in, temperatures near 32 degrees Fahrenheit there were unheard of. But since the 1980s, this region has warmed by around 1.5 degrees Fahrenheit per decade — four times faster than the global pace — making it all the more likely that temperatures will cross the melting point.

If you see a house cat, the    1    are high that it will have white paws, a look that many owners affectionately call“socks.” But socks are rarely seen in wildcats, the elusive and undomesticated cousin of the house cat, so why do so many pet cats sport furry white feet?

As it turns out, this story started about 10,000 years ago, when humans and cats     2       life was better together.

This    3    eventually led to uber-prevalent socks on cats, as well as other well-known coat patterns, said Leslie Lyons, professor emerita and head of the Feline Genetics Laboratory at the University of Missouri College of Veterinary Medicine.

“As humans became farmers and started staying in one place, they had grain stores and waste piles” that attracted rodents, Lyons said. It was a mutually beneficial arrangement: the humans had fewer rodents to deal with and the cats got an easy meal.

The wild, undomesticated ancestor species of house cats, Felis silvestris, lives in Africa and Eurasia. These felines are tasty snacks as kittens and stealthy predators as adults, so     4     born with a coat that offers camouflage (保护色) have tended to survive and reproduce.

But not every F. silvestiis is born with a coat that blends into its habitat.

“Genetic mutations are occurring all the time.” Lyons said.

There isn’t much evidence to indicate why early cat people chose the individuals they did, but Lyons said the range of coats seen on modern domestic cats shows that our agrarian ancestors favored cats with markings that would have     5    with their camouflage.

In its native mixed forest or scrub desert environment, a cat with stark white paws would have stood out to predators and prey.

When humans started taking an interest in cats, these white paws would have stood out to them, too. “There were probably people saying, ‘I particularly like that kitten because it has white feet . Let’s make sure it survives’”, Lyons said.

Humans probably also    6    cats who were calm and comfortable around humans, Lyons said. Behavioral traits seem unrelated to coat color, but for reasons that scientists don’t fully understand, white spots tend to appear when the     7    individuals are selected and bred.

These    8    fur colors and markings emerge while a cat embryo is developing. The cells that give cat fur its color first appear as neural crest cells, which are located along what will become the back, Lyons said.

Then, those cells slowly migrate down and around the body. If those waves of cells move far enough to meet each other on the cat’s front side, the embryo will be born a solid-colored kitten, such as an all-black or all-orange cat. Felines     9    white feet, faces, chests and bellies when these cells don’t quite make it all the way.

So, the next time you see a kitty wearing white socks, you’ll know that this     10     feature is a result of genetic mutations, domestication and developmental biology. Although if you try telling the cat that, it will probably just look at you quizzically before sauntering away.

7 . Science may never know the secrets to memories of the California sea hare, a foot-long sea snail. But a research team claim to have made progress in _______ the simplest kind of memory a mollusk (软体动物) might form, and, with a swift injection, managed to _______ one sea snail’s memory to another.

The kinds of memories that start a defensive reaction in the snails are encoded not in the _______between brain cells, but in RNA molecules (分子), according to David Glanzman, a biologist at UCLA. To _______ the idea, Glanzman implanted wires into the tails of California sea hares and gave them a series of electric shocks. The procedure made the animals so _______ that when they were touched, they contracted parts of their bodies intensely. Glanzman compares the reaction to being nervous after an earthquake: the memory of the event causes a(n) _______ response to any loud noise. After sensitizing the sea snails, Glanzman took RNA out from them and _______ it into new sea snails to see what would happen. He then found the new ones are _______ sensitized, suggesting the “memory” of the electrical shocks had been transplanted. According to Glanzman and his research team, the experiment shows that _______ parts of the memory trace are held in RNA, rather than in the connectivity of brain cells.

However, the work has not yet found widespread ________. “Further work needs to be carried out to determine whether these phenomena are obvious and what is the ________ of such phenomena,” said Prof Vann at Cardiff University. “While a sea snail is a fantastic model, we must be very ________ in drawing comparisons to human memory processes, which are much more complex.”

Tomás Ryan at Trinity College Dublin, is ________. “This work takes us down an interesting road, but I have doubt about it and I don’t think they’ve transplanted a memory,” he said. “This work tells me that maybe the most basic behavioral responses involve some kind of change in the animal.”

8 . One summer midnight several years ago, standing outside a wooden cabin in Michigan River, I looked up. The sky was filled with thousands of stars, the sight of which was almost enough to make me, a non-believer, offer a word of ___________ up into the star-filled sky. But to whom? Perhaps to Johan Eklof, author of The Darkness Manifesto.

As a bat scientist, Eklof’s work on bats requires a specific kind of darkness—the ___________kind, unpolluted by light. But this category of darkness is ___________. In the 1980s, Eklof tells readers, two-thirds of the churches in Sweden’s southwest housed bat colonies. Not any longer. “Today, forty years later, research I’ve done with my colleagues shows that this number has been reduced by a third, ___________ light pollution and other factors. Because the churches are all ___________ like carnivals(嘉年华) in the night,” he writes. “We are surrounding ourselves with light.”

Excess light is incredibly ___________ to the complex eco-systems nocturnal (夜间活动的) animals inhabit. It ___________ away the bats that Eklof studies. It frightens light-sensitive moths, leaving them easily ___________ to predation(捕食) or flying endlessly into lights that will never return their love. Baby turtles crawl away from the shoreline toward the lights of distant coastal cities and reef fish eggs go unhatched. Birds do not migrate ___________ and even they forget to sing. Modern advancements such as LED lights could significantly reduce some of the worst impacts, but they have not. At least, not yet.

It is worth mentioning that middle-aged writer like Eklof can ____________ for a darker world — for darkened campuses and unlit parking lots. But darkness is not safe for everyone. We need to address the social issues that make lighted places so ____________ in the first place.

The bottom line: We can change if we want to. Some of the solutions to light pollution— motion-detecting lights, shielded lights that do not ____________ light upward, artificial light with wavelengths that is similar to natural light—are already within our grasp, if we just ____________ them. “We could just turn it all off, but I guess we don’t want to,” said Eklof in a recent interview. “____________, it’s vital we find a middle way.”

Right now it is hard to know what that middle way might look like. In 50 years, every city could be equipped with an array of programmed and ____________ low-impact LED lights. Or we might have completely forgotten what darkness is—the sky filled with little moons.